This is a BO tester made by qxc (a well known American player). This lets you test out builds multiple times by restarting the map with a standard 1v1 start, ie a gather point and harvesters.
Shift+1 - resets map with Protoss
Shift+2 - resets map with Terran
Shift+3 - resets map with Zerg
To use this map, open the file with Starcraft II Editor.exe and then hit Ctrl+F9.
Source:
http://www.teamliquid.net/forum/viewmessage.php?topic_id=126942